/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.gen;

import com.android.dx.rop.code.RegisterSpec;

/**
 * A temporary variable that holds a single value.
 */
public final class Local<T> {

	private final Code code;
	final Type<T> type;
	private int reg = -1;
	private RegisterSpec spec;

	private Local(Code code, Type<T> type) {
		this.code = code;
		this.type = type;
	}

	static <T> Local<T> get(Code code, Type<T> type) {
		return new Local<T>(code, type);
	}

	/**
	 * Assigns registers to this local.
	 * 
	 * @return the number of registers required.
	 */
	int initialize(int reg) {
		this.reg = reg;
		this.spec = RegisterSpec.make(reg, type.ropType);
		return size();
	}

	int size() {
		return type.ropType.getCategory();
	}

	RegisterSpec spec() {
		if (spec == null) {
			code.initializeLocals();
			if (spec == null) {
				throw new AssertionError();
			}
		}
		return spec;
	}

	public Type getType() {
		return type;
	}

	@Override
	public String toString() {
		return "v" + reg + "(" + type + ")";
	}
}
